Question

need help

Answer 1

Ok, post question you need help with.

Answer 2

where u need help?/

Answer 3

how to prove the identify without evaluating the determinants for number 8 - 11

Answer 4

\(\large \begin{align} \color{black}{\text{use Elementary Row and Column Operations}\\~\\
\begin{vmatrix}a_1 & b_1 & a_1+b_1+c_1 \\ a_2 & b_2 & a_2+b_2+c_2 \\ a_3 & b_3 & a_3+b_3+c_3 \end{vmatrix} \\~\\
C_3-(C1+C2)\\~\\
\begin{vmatrix}a_1 & b_1 & a_1+b_1+c_1-(a_1+b_1) \\ a_2 & b_2 & a_2+b_2+c_2-(a_2+b_2) \\ a_3 & b_3 & a_3+b_3+c_3-(a_3+b_3) \end{vmatrix} \\~\\
\begin{vmatrix}a_1 & b_1 & c_1 \\ a_2 & b_2 & c_2 \\ a_3 & b_3 & c_3 \end{vmatrix} \\~\\
}\end{align}\)